In conventional optical network technology field, such as Synchronous Digital Hierarchy (SDH), Synchronous Optical Network (SONET) and Optical Transmission Network (OTN), the network is mainly constructed in the form of a Self-Healing Ring, of which the drawback lies in the relatively low bandwidth utilization ratio. Furthermore, static configuration made by network manager is often adopted in the conventional optical network technology, which is relatively complicated and has large consumption of time. With the emergence of various requirements of multi-service, high bandwidth, high survivability, and fast provision of connection, the existing network architecture and networking mode are strongly impacted, and therefore the network topology will evolve from the conventional ring network to the Mesh Network. Accordingly, the network connection provision mode will also have a transition from the permanent connection provisioned statically to the signaling-based Soft Permanent Connection (SPC) and Switch Connection (SC), which become a core technology in the development of optical network. Therefore, this new type of optical transmission network is named as ASON by the International Telecommunication Union—Telecommunication Standardization Sector (ITU-T), in which the concept of “control plane” is introduced for the establishment, modification, and maintenance of the network connection, and for the restoration of the connection under the condition of network failure. In addition, implementation of ASON signaling includes the Generalized Multi-Protocol Label Switching (GMPLS) protocol developed by Internet Engineering Task Force (IETF).
In a Mesh network, restoration mechanisms that are currently used include: restoration path pre-calculation, restoration path resource reservation, restoration path resource pre-selection, and dynamic re-routing. With respect to the problem concerning how to restore the service when failure occurs in a working path with the above various restoration mechanisms, currently the research emphases is focused on the approach that a first node initiates a signaling unidirectionally to establish a restoration path, and then the service is switched from the failed path to the restoration path. The main process is as follows: as shown in FIG. 1, assuming that node A is the first node, when detecting the occurrence of failure in this path, node B in the working path W (A→B→E→H→J) notifies information of failure status to the node A in the working path, and then node A takes charge of the establishment of the restoration path, i.e. node A creates a signaling message first, and then the connection of each node in the restoration path is established hop by hop in a direction from node A to node J with information of restoration path carried, until the entire restoration path is completed, and finally the service is switched from the failed path to the restoration path P (A→C→D→F→G→I→J), so that the service is restored. The signaling messages created include: resource reservation setup protocol with traffic-engineering extensions (RSVP-TE) and Constrained Route-Label Distribution Protocol (CR-LDP).
In this restoration mechanism, the distributed characteristic in the ASON is not exerted sufficiently. The signaling is only initiated in a single direction (first node→end node) when establishing a restoration path, which results in a long time for establishing a restoration path, and a low implementation efficiency, whereby the transmission of service is affected or even interrupted.